There was no official confirmation on how many people were arrested, but the Muslim Brotherhood website put the number at more than 270.

In Alexandria, 33 people were injured as demonstrators threw rocks at security forces trying to disperse a crowd from one neighborhood, eye witnesses said.

Various opposition groups -- including the banned Muslim Brotherhood group, whose candidates are forced to run as independents -- have accused the ruling National Democratic Party (NDP) of using its power to suppress voices critical of President Mubarak's almost-30-year rule.

The ruling party has dismissed the accusations.

Opposition calls for internationalal election monitors are unnecessary, said the ruling party general secretary, Safwat al-Shareef.